revisiting defaults in description logics – and their role in aligning ontologies. (jist 2014)
TRANSCRIPT
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IntroductionContributionFree defaultsConclusion
Revisiting default description logics – and theirrole in aligning ontologies
Kunal Sengupta 1 Pascal Hitzler 1 Krzysztof Janowicz 2
1Wright State University, Dayton OH 45435, USA
2University of California, Santa Barbara, USA
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
1 IntroductionMotivationExamplesProposed Solution
2 Contribution
3 Free defaultsSemanticsDecidability
4 Conclusion
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
![Page 3: Revisiting defaults in description logics – and their role in aligning ontologies. (JIST 2014)](https://reader031.vdocuments.site/reader031/viewer/2022032218/55abd41d1a28ab34048b4704/html5/thumbnails/3.jpg)
IntroductionContributionFree defaultsConclusion
MotivationExamplesProposed Solution
1 IntroductionMotivationExamplesProposed Solution
2 Contribution
3 Free defaultsSemanticsDecidability
4 Conclusion
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
![Page 4: Revisiting defaults in description logics – and their role in aligning ontologies. (JIST 2014)](https://reader031.vdocuments.site/reader031/viewer/2022032218/55abd41d1a28ab34048b4704/html5/thumbnails/4.jpg)
IntroductionContributionFree defaultsConclusion
MotivationExamplesProposed Solution
Motivation
Heterogeneity is everywhere: Linked Data, Ontologies, Worldwide web
How to have ontology mappings that respect heterogeneity?
OWL (Description logics) is not suitable for ontology mapping
Why, you ask?
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
![Page 5: Revisiting defaults in description logics – and their role in aligning ontologies. (JIST 2014)](https://reader031.vdocuments.site/reader031/viewer/2022032218/55abd41d1a28ab34048b4704/html5/thumbnails/5.jpg)
IntroductionContributionFree defaultsConclusion
MotivationExamplesProposed Solution
Motivation
Heterogeneity is everywhere: Linked Data, Ontologies, Worldwide web
How to have ontology mappings that respect heterogeneity?
OWL (Description logics) is not suitable for ontology mapping
Why, you ask?
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
![Page 6: Revisiting defaults in description logics – and their role in aligning ontologies. (JIST 2014)](https://reader031.vdocuments.site/reader031/viewer/2022032218/55abd41d1a28ab34048b4704/html5/thumbnails/6.jpg)
IntroductionContributionFree defaultsConclusion
MotivationExamplesProposed Solution
Motivation
Heterogeneity is everywhere: Linked Data, Ontologies, Worldwide web
How to have ontology mappings that respect heterogeneity?
OWL (Description logics) is not suitable for ontology mapping
Why, you ask?
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
![Page 7: Revisiting defaults in description logics – and their role in aligning ontologies. (JIST 2014)](https://reader031.vdocuments.site/reader031/viewer/2022032218/55abd41d1a28ab34048b4704/html5/thumbnails/7.jpg)
IntroductionContributionFree defaultsConclusion
MotivationExamplesProposed Solution
Motivation
Heterogeneity is everywhere: Linked Data, Ontologies, Worldwide web
How to have ontology mappings that respect heterogeneity?
OWL (Description logics) is not suitable for ontology mapping
Why, you ask?
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
![Page 8: Revisiting defaults in description logics – and their role in aligning ontologies. (JIST 2014)](https://reader031.vdocuments.site/reader031/viewer/2022032218/55abd41d1a28ab34048b4704/html5/thumbnails/8.jpg)
IntroductionContributionFree defaultsConclusion
MotivationExamplesProposed Solution
An example!
Ontology A
a:hasWife v a:hasSpouse
symmetric(a:hasSpouse)
∃a:hasSpouse.a:Female v a:Male
∃a:hasSpouse.a:Male v a:Female
a:hasWife(a:john, a:mary)
a:Male(a:john)
a:Female(a:mary)
a:Male u a:Female v ⊥
Mappings
a:hasSpouse ≡ b:hasSpouse
a:Male ≡ b:Male
a:Female ≡ b:Female
Ontology B
symmetric(b:hasSpouse)
b:hasSpouse(b:mike, b:david)
b:Male(b:david)
b:Male(b:mike)
b:Female(b:anna)
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
MotivationExamplesProposed Solution
An example!
Ontology A
a:hasWife v a:hasSpouse
symmetric(a:hasSpouse)
∃a:hasSpouse.a:Female v a:Male
∃a:hasSpouse.a:Male v a:Female
a:hasWife(a:john, a:mary)
a:Male(a:john)
a:Female(a:mary)
a:Male u a:Female v ⊥
Mappings
a:hasSpouse ≡ b:hasSpouse
a:Male ≡ b:Male
a:Female ≡ b:Female
Ontology B
symmetric(b:hasSpouse)
b:hasSpouse(b:mike, b:david)
b:Male(b:david)
b:Male(b:mike)
b:Female(b:anna)
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
MotivationExamplesProposed Solution
An example!
Ontology A
a:hasWife v a:hasSpouse
symmetric(a:hasSpouse)
∃a:hasSpouse.a:Female v a:Male
∃a:hasSpouse.a:Male v a:Female
a:hasWife(a:john, a:mary)
a:Male(a:john)
a:Female(a:mary)
a:Male u a:Female v ⊥
Mappings
a:hasSpouse ≡ b:hasSpouse
a:Male ≡ b:Male
a:Female ≡ b:Female
Ontology B
symmetric(b:hasSpouse)
b:hasSpouse(b:mike, b:david)
b:Male(b:david)
b:Male(b:mike)
b:Female(b:anna)
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
MotivationExamplesProposed Solution
owl:sameAs example
Ontology A
a:Airport(a:kennedy)
a:Airport v a:Place
Ontology B
b:President(b:kennedy)
b:President v b:Person
b:Place u b:Person v ⊥
Mappings
a:Place ≡ b:Place
owl:sameAs(a:kennedy,b:kennedy)
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
MotivationExamplesProposed Solution
owl:sameAs example
Ontology A
a:Airport(a:kennedy)
a:Airport v a:Place
Ontology B
b:President(b:kennedy)
b:President v b:Person
b:Place u b:Person v ⊥
Mappings
a:Place ≡ b:Place
owl:sameAs(a:kennedy,b:kennedy)
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
MotivationExamplesProposed Solution
Using defaults for ontology mapping
Use statements like b:hasSpouse vd a:hasSpouse to denotemappings
For each pair that satisfies b:hasSpouse assume it satisfiesa:hasSpouse unless it causes an inconsistency
Assuming a:hasSpouse(b:mike, b:david) causes aninconsistency
The pair (b:mike, b:david) is treated as an exception to thestatement b:hasSpouse vd b:hasSpouse
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
MotivationExamplesProposed Solution
Solution
Use defaults to denote mappings, such that exceptions areallowed.
b:hasSpouse : a:hasSpouse
a:hasSpouse
But DLs + Defaults = Undecidable logics [Baader, Hollunder95].
Workaround: Defaults apply only to named individuals[Baader, Hollunder 95].
What about un-named individuals?
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
MotivationExamplesProposed Solution
Solution
Use defaults to denote mappings, such that exceptions areallowed.
b:hasSpouse : a:hasSpouse
a:hasSpouse
But DLs + Defaults = Undecidable logics [Baader, Hollunder95].
Workaround: Defaults apply only to named individuals[Baader, Hollunder 95].
What about un-named individuals?
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
![Page 16: Revisiting defaults in description logics – and their role in aligning ontologies. (JIST 2014)](https://reader031.vdocuments.site/reader031/viewer/2022032218/55abd41d1a28ab34048b4704/html5/thumbnails/16.jpg)
IntroductionContributionFree defaultsConclusion
1 IntroductionMotivationExamplesProposed Solution
2 Contribution
3 Free defaultsSemanticsDecidability
4 Conclusion
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
Contribution
Free defaults
Application of defaults not limited to named individuals∗∗
Defaults with role inclusions are also decidable.
A new, more powerful language to define mapping betweenontologies.
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
Contribution
Free defaults
Application of defaults not limited to named individuals∗∗
Defaults with role inclusions are also decidable.
A new, more powerful language to define mapping betweenontologies.
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
![Page 19: Revisiting defaults in description logics – and their role in aligning ontologies. (JIST 2014)](https://reader031.vdocuments.site/reader031/viewer/2022032218/55abd41d1a28ab34048b4704/html5/thumbnails/19.jpg)
IntroductionContributionFree defaultsConclusion
Contribution
Free defaults
Application of defaults not limited to named individuals∗∗
Defaults with role inclusions are also decidable.
A new, more powerful language to define mapping betweenontologies.
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
![Page 20: Revisiting defaults in description logics – and their role in aligning ontologies. (JIST 2014)](https://reader031.vdocuments.site/reader031/viewer/2022032218/55abd41d1a28ab34048b4704/html5/thumbnails/20.jpg)
IntroductionContributionFree defaultsConclusion
SemanticsDecidability
1 IntroductionMotivationExamplesProposed Solution
2 Contribution
3 Free defaultsSemanticsDecidability
4 Conclusion
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Syntax
A new operator vd that represents default inclusions
C vd D is a default class inclusion
A default-knowledge-base is denoted as (KB, δ), where KB isa DL knowledge base and δ is a set of default axioms
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Semantics (Intuitive)
C vd D
Every named individual in C is also in D unless it causes aninconsistency
Every un-named individual in C is also in D (it behavesexactly same as v)
Exceptions occur only in named individuals
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Default satisfying individuals
A named individual a is said to satisfy a default C vd D if:
1 a ∈ CI ,DI , or
2 a ∈ (¬C )I
Key: We want to maximize the sets of individuals that satisfy eachdefault
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Default satisfying individuals
A named individual a is said to satisfy a default C vd D if:
1 a ∈ CI ,DI , or
2 a ∈ (¬C )I
Key: We want to maximize the sets of individuals that satisfy eachdefault
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Interpretation
An interpretation I for a default-knowledge-base (KB, δ)
1 (∆I , .I) as usual
2 Additionally, δI denotes the tuple (X I1 , . . . ,XIn )
3 X Ii is the set of interpreted named individuals satisfying thei th default Ci vd Di
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Preference relation >KB,δ
I, J are two interpretations of default-knowledge-base (KB, δ).Then I >KB,δ J if:
1 aI = aJ for all a ∈ KB
2 X Ii ⊇ XJi for all 1 ≤ i ≤| δ |3 X Ii ⊃ XJi for some 1 ≤ i ≤| δ |
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Example
Knowledge Base
Bird(a)
Bird(b)
Penguin(c)
Penguin v Bird
Penguin u Fly v ⊥δ = {Bird vd Fly}
Interpretation I
∆I = {a, b, c}BirdI = {a, b, c}
PenguinI = {c}FlyI = {a}δI = ({a})
Interpretation J
∆J = {a, b, c}BirdJ = {a, b, c}
PenguinJ = {c}FlyJ = {a, b}δJ = ({a, b})
J >KB,δ I
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Example
Knowledge Base
Bird(a)
Bird(b)
Penguin(c)
Penguin v Bird
Penguin u Fly v ⊥δ = {Bird vd Fly}
Interpretation I
∆I = {a, b, c}BirdI = {a, b, c}
PenguinI = {c}FlyI = {a}δI = ({a})
Interpretation J
∆J = {a, b, c}BirdJ = {a, b, c}
PenguinJ = {c}FlyJ = {a, b}δJ = ({a, b})
J >KB,δ I
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
d-model
An interpretation I of (KB, δ) is called a default model or d-modelif
I satisfies all axioms of KB
CIi ⊆ DIi , for all un-named individuals
I is maximal with respect to the preference relation >KB,δ
A default-knowledge-base that has a d-model is called d-satisfiable.Note: Reiter’s normal defaults are always satisfiable.
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
d-entailment
An axiom α is d-entailed by a default-knowledge-base if it istrue in all the d-models.
We follow skeptical reasoning.
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Decidability
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Some notations
IndKB is the set of all the named individuals occurring in KB.
P(IndKB) is the power set of IndKB
Pn(IndKB) = P(IndKB)× . . .n-1 times × P(IndKB), where n isthe cardinality of δ
IndKB = {a, b}
P(IndKB) = {{a}, {b}, {a, b}}Pn(IndKB) ={({a}, {a}), ({a}, {b}), ({b}, {a}), . . . , ({a, b}, {a, b})}, for| δ |= 2
Note: Pn(IndKB) is a set of n-tuples that contains all thepossible combinations for δI
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Some notations
IndKB is the set of all the named individuals occurring in KB.
P(IndKB) is the power set of IndKB
Pn(IndKB) = P(IndKB)× . . .n-1 times × P(IndKB), where n isthe cardinality of δ
IndKB = {a, b}P(IndKB) = {{a}, {b}, {a, b}}
Pn(IndKB) ={({a}, {a}), ({a}, {b}), ({b}, {a}), . . . , ({a, b}, {a, b})}, for| δ |= 2
Note: Pn(IndKB) is a set of n-tuples that contains all thepossible combinations for δI
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Some notations
IndKB is the set of all the named individuals occurring in KB.
P(IndKB) is the power set of IndKB
Pn(IndKB) = P(IndKB)× . . .n-1 times × P(IndKB), where n isthe cardinality of δ
IndKB = {a, b}P(IndKB) = {{a}, {b}, {a, b}}Pn(IndKB) ={({a}, {a}), ({a}, {b}), ({b}, {a}), . . . , ({a, b}, {a, b})}, for| δ |= 2
Note: Pn(IndKB) is a set of n-tuples that contains all thepossible combinations for δI
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Some notations
IndKB is the set of all the named individuals occurring in KB.
P(IndKB) is the power set of IndKB
Pn(IndKB) = P(IndKB)× . . .n-1 times × P(IndKB), where n isthe cardinality of δ
IndKB = {a, b}P(IndKB) = {{a}, {b}, {a, b}}Pn(IndKB) ={({a}, {a}), ({a}, {b}), ({b}, {a}), . . . , ({a, b}, {a, b})}, for| δ |= 2
Note: Pn(IndKB) is a set of n-tuples that contains all thepossible combinations for δI
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Knowledge base re-writing
Consider some P = (X1, . . . ,Xn) ∈ Pn(IndKB). Then KBP isobtained by adding the following axioms to KB, for each Ci vd Di
1 Xi ≡ (Ci u Di u {a1, . . . , ak}) t (¬Ci u {a1, . . . , ak})2 Ci u ¬{a1, . . . , ak} v Di
Intuition
Recall, an individual a satisfies a default C vd D ifa ∈ CI ,DI or a ∈ (¬C )I
Unknowns always satisfy the defaults
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Knowledge base re-writing
Consider some P = (X1, . . . ,Xn) ∈ Pn(IndKB). Then KBP isobtained by adding the following axioms to KB, for each Ci vd Di
1 Xi ≡ (Ci u Di u {a1, . . . , ak}) t (¬Ci u {a1, . . . , ak})
2 Ci u ¬{a1, . . . , ak} v Di
Intuition
Recall, an individual a satisfies a default C vd D ifa ∈ CI ,DI or a ∈ (¬C )I
Unknowns always satisfy the defaults
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Knowledge base re-writing
Consider some P = (X1, . . . ,Xn) ∈ Pn(IndKB). Then KBP isobtained by adding the following axioms to KB, for each Ci vd Di
1 Xi ≡ (Ci u Di u {a1, . . . , ak}) t (¬Ci u {a1, . . . , ak})2 Ci u ¬{a1, . . . , ak} v Di
Intuition
Recall, an individual a satisfies a default C vd D ifa ∈ CI ,DI or a ∈ (¬C )I
Unknowns always satisfy the defaults
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Decidability of d-satisfiability
Lemma
Let (KB, δ) be a default-knowledge-base, if KBP is classicallysatisfiable for some P ∈ Pn(IndKB), then (KB, δ) is d-satisfiable.
Theorem
The task of determining d-satisfiability of default-knowledge-basesis decidable.
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Decidability of d-satisfiability
Lemma
Let (KB, δ) be a default-knowledge-base, if KBP is classicallysatisfiable for some P ∈ Pn(IndKB), then (KB, δ) is d-satisfiable.
Theorem
The task of determining d-satisfiability of default-knowledge-basesis decidable.
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Decidability of d-entailment tasks
For non-montonic logics such as free-defaults entailment tasksare not directly reducible to satisfiability check
We need to check all models for d-entailments
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Proof sketch
KBP is constructed using P ∈ Pn(IndKB)
Pn(IndKB) is finite
An order can be computed on Pn(IndKB) based on maximalityof its elements (finite time)
Construct a set MaxP consisting of maximal classicallysatisfiable KBPs
MaxP is generated in finite time due to the finiteness ofPn(IndKB)
Theorem
A DL axiom α is entailed by a default-knowledge-base (KB, δ) iff itis classically entailed by every KBP ∈ MaxP
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Proof sketch
KBP is constructed using P ∈ Pn(IndKB)
Pn(IndKB) is finite
An order can be computed on Pn(IndKB) based on maximalityof its elements (finite time)
Construct a set MaxP consisting of maximal classicallysatisfiable KBPs
MaxP is generated in finite time due to the finiteness ofPn(IndKB)
Theorem
A DL axiom α is entailed by a default-knowledge-base (KB, δ) iff itis classically entailed by every KBP ∈ MaxP
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Role defaults
Note: Similar construction can be used to show decidability of roledefaults under the semantics of free-defaults
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
SemanticsDecidability
Back to the example
Now, the mapping can be denoted asb:hasSpouse vd a:hasSpouse, a:hasSpouse vd b:hasSpouse
b:hasSpouseI = {(b:david, b:mike), (b:mike, b:david),(a:john, a:marry), (a:marry, a:john)}
a:hasSpouseI = {((a:john, a:marry), (a:marry, a:john)}
Notice that heterogeneity is still respected and at the sametime relations can be carried over
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
1 IntroductionMotivationExamplesProposed Solution
2 Contribution
3 Free defaultsSemanticsDecidability
4 Conclusion
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
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IntroductionContributionFree defaultsConclusion
Conclusion
Drawback
The free-defaults don’t work when un-named individuals areimplicit exceptions
Future work
Investigation of decidability of more general defaults in DLs
Effecient algorithmization of d-entailment tasks
Implementation
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
![Page 48: Revisiting defaults in description logics – and their role in aligning ontologies. (JIST 2014)](https://reader031.vdocuments.site/reader031/viewer/2022032218/55abd41d1a28ab34048b4704/html5/thumbnails/48.jpg)
IntroductionContributionFree defaultsConclusion
Conclusion
Drawback
The free-defaults don’t work when un-named individuals areimplicit exceptions
Future work
Investigation of decidability of more general defaults in DLs
Effecient algorithmization of d-entailment tasks
Implementation
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)
![Page 49: Revisiting defaults in description logics – and their role in aligning ontologies. (JIST 2014)](https://reader031.vdocuments.site/reader031/viewer/2022032218/55abd41d1a28ab34048b4704/html5/thumbnails/49.jpg)
IntroductionContributionFree defaultsConclusion
Questions?
DaSe Lab for Data Semantics at Wright state university
Twitter : @DaSeLab, @sengupta kunal
Website : http://wright.edu/~sengupta.4
Topics : Semantic Web, Knowledge representation andreasoning, Description Logics, Rules, Ontology alignment,Applications ...
Kunal Sengupta , Pascal Hitzler , Krzysztof Janowicz Revisiting default description logics (JIST 2014)